1. Field of Invention
This invention relates to a tamper-evident closure seal; more particularly, to a closure seal for cartons that prevents undetectable entry to the carton's contents.
2. Description of the Related Art
Manufacturers and distributors of consumer products have been sensitive for many years to the potential danger posed by persons gaining unauthorized access to their packaged products, particularly if that access is not evident to a subsequent buyer of the product. Manufacturers of consumer products, as well as packaging manufacturers, have developed a great variety of "tamper-evident" or "tamper-resistant" packaging.
Schaefer et al., U.S. Pat. No. 4,557,505, issued Dec. 10, 1985, discloses a tamper indicating package-closure tape that has a visible message which is changed when the tape is stressed. The tape provides one message when the package is sealed and a different message when it has been opened, because opening the package causes a transparent material to become opaque.
Bernardelli, U.S. Pat. No. 5,020,831, issued Jun. 4, 1991, discloses an interlaced multilayer that has a latent configuration that is rendered visible and irreversible by being transposed to a new support, for example by a label being stripped from a surface.
Johnston, U.S. Pat. No. 5,265,794, issued Nov. 30, 1993, discloses a tamper-evident folding carton that includes flaps sealed to one another. Opening a flap causes a tamper-indicating message to appear in a window at the carton end.
None of the references discussed above address a problem that arises when a product is sold in a carton that has one or more flaps ("tuck" and "dust" flaps) that simply fold into the carton. Those flaps are readily sealed by a closure seal that bridges the seam between an end and a side of the carton. However, if that seal is cut along the seam and subsequently resealed by a seal that is transparent and congruent with the original, the access to the contents of the carton can be concealed.